I've had a reply from Image. The chap really knew his stuff thankfully.
His reply below refferance a 2017 T32:
"Hi Paul,
No problem we have been dealing with petrol heads for 30 years pleased to say as most know what they want.
Regarding the loadings this is up to the maximum our rims will take because the centres are billet so can be made to suit the loading and this is 950kg per wheel.
Wheels are made to order so you can have them with centre caps and wheel nuts on show or hub caps or lock plates.
You can also have lock plates and spinners if you want.
They can be all polished and anodise or all painted or polished rims with painted centres.
Regards Harry"
I'm seriously considering the set I linked above 'Billet 46' in 20" staggered 9.5" rear and 8.5" fronts ET45